Prince and his co-driver were due in California at 1 p.m. Tuesday, where they were going to drop off 25,000 pounds of frozen pizza.

But they stumbled on what the National Weather Service is calling “a crippling, historic blizzard.”

“It was pretty nasty when we first got into it,” he said. “But then it turned into a whiteout.”

Prince, who has been a long-haul driver for nine years, said in a submission to CNN’s iReport that he’d never seen it so bad. The line of trucks on the westbound side of the interstate was five to six miles long.

A day later, three people were dead, and 21 states and 45 million people were under some form of winter weather watch, warning or advisory.

The piling snow snapped tree branches, brought down power lines and made it tough for snowplows and utility crews to keep up.

In Shawnee, Kansas, the roof of a horse arena collapsed under the weight of snow Tuesday morning, CNN affiliate KSHB reported. It was one of several such collapses in the region because of the wet heavy snow, the station said.

No injuries were reported in those collapses, but a person died Monday in a roof collapse in hard-hit Woodward, Oklahoma, said that city’s mayor, Roscoe Hill.

The other two deaths came in Kansas on Monday in separate weather-related accidents on Interstate 70. One accident happened in Sherman County and the other in Ellis County, the Kansas National Guard said.

As the storm moved northeast, the snow stopped, temperatures rose and roads were clearing in the Kansas City area. But the Kansas Department of Transportation reported early Tuesday that three of its plows had gotten stuck. The agency asked that motorists give crews more time to clear roads before trying to venture out.

More than 56,000 customers in Kansas and Missouri were without power Tuesday afternoon, the Kansas National Guard said. The bulk of the outages — 45,000 — were in the Kansas City region straddling the border between Kansas and Missouri.

Most flights out of Kansas City International Airport were canceled.

Roads were still snow-covered, but improving, in northwestern Missouri, the state Department of Transportation said on Twitter. The agency continued to discourage travel.

Forecasters expected the storm to bring up to 18 inches of snow to parts of eastern Kansas, Missouri and Illinois a day after plastering southern Kansas, Oklahoma and Texas. Winter storm watches and warnings or weather advisories stretched from Oklahoma to Michigan.

Also on Tuesday, a stretch of Interstate 40 east of Amarillo, Texas, was closed in both directions because of what the Texas Department of Transportation called “extremely icy conditions.”

While the back-to-back snowstorms were frustrating for some, others put a positive spin on the experience. Jim Service of Overland Park, Kansas, spaced out the work of clearing last week’s snowfall over four days. He finished Sunday, just in time for this storm.

After a warm-up session clearing Tuesday’s snow — much wetter and heavier than last week’s — he retreated inside with a Clive Cussler novel and planned to enjoy the day off. Like many others, Service’s company called off work Tuesday at the behest of state officials who warned that the storm was too dangerous for people to be on the roads.

“It’s great for me,” he said.

The Kansas National Guard warned that continued snowfall and gusty winds would make travel tricky through Wednesday.

In Woodward, emergency vehicles were still having trouble getting around Tuesday, a day after the storm dropped more than 15 inches of snow.

Crews dispatched to a house fire Monday had trouble reaching the home because of 4-foot snowdrifts. The snowplow sent to free the firefighters also got stuck. Even Tuesday, emergency vehicles still were having a tough time getting around.

“We’re in such a mess,” said Hill, the mayor.

Whiteout conditions

The storm follows one last week that paralyzed a broad swath of the Plains and Midwest with more than a foot of snow. Parts of Oklahoma, Kansas, Missouri and other states were affected.

The storm prompted a state of emergency declaration in Kansas and parts of Oklahoma, bringing whiteout conditions to southern parts of those states and Texas.

Schools in Wichita, Kansas, were closed Tuesday for a fourth straight day after last week’s storm, which dumped a record 14.2 inches on the city. Wichita has received 21 inches of snow in February, breaking a record that had stood for 100 years, the National Weather Service said. And it all fell in the past six days.

Amarillo, not far from where truck driver Prince was stuck, saw 19 inches of snow Monday, along with fierce winds that whipped the snow into whiteout conditions.

By Monday night, though, conditions had improved in the Texas panhandle.

“Things have cleared up now,” said CNN iReporter Julie Swift, a student at Wayland Baptist University in Plainview. “The snow is starting to melt and the roads are improving. It’s still very windy, though.”

Rain, ice elsewhere

Also on tap for Tuesday: up to 7 inches of much-needed snow in the Chicago and Detroit areas; high winds in Tennessee, North Carolina and southern Virginia; the threat of ice in West Virginia; and more drenching rain in the Southeast, the National Weather Service said.

In the Southeast, gusty winds and flooding were the concerns.

In Mobile, Alabama, the storm was expected to bring heavy rain and 30 mph wind gusts early Tuesday. Tornado watches were up in southeast Georgia and parts of Florida through Tuesday afternoon. Flood watches and warnings were in place from Louisiana to South Carolina.